Artificial fingers and hand mechanism



1958 D. B. BECKER ARTIFICIAL FINGERS AND HAND MECHANISM 2 Sheets-Sheet 1Filed Jan. '7, 1955 ATTORNEY Nov. 11, 1958 D. B ECKER 2,859,450

ARTIFICIAL FINGERS AND HAND MECHANISM Filed Jan. 7, 1955 2 Sheets-Sheet2 Il 79 61 I 619 68 I I 73 g5 7 74 6/ 9 66 i3 /9/ J0 D A w 10 l Mt 1'37:9 615 I'I'IIII INVENTOR Dan/e/ 5. Becker ATTORNEY United rates PatentARTIFICIAL FlNGERS AND HAND MECHANISM Daniel B. Becker, St. Paul, Minn.Application January 7, 1955, Serial No. 480,386

13 Claims. (Cl. 312.7)

This invention relates to an improvement in artificial fingers and animprovement in finger operating mechanism. More particularly, thisimprovement in the art concerns plastic flexible fingers and theirindependent attachment and operation as bending fingers to artificialhands.

Flexible artificial fingers having the appearance and seeming action ofnormal or natural finger movement has long been the aim of the industrywhich makes artificial hands. While flexible skin appearing plasticcoverings for the fingers and hands are known, the spiral spring fingerhas most nearly approached this objective. Otherwise artificial fingersare stiff jointed and bend from the one knuckle only depending upon apermanent curvature of the finger for any clasping or grasping action.In any event the only known successfully made and operating artificialfingers have not been of a relatively soft or resilient characterresembling the natural flesh, bone, action and appearance of a normalfinger. In addition it has heretofore not been possible to successfullycontrol the finger operating pressure in combination With a flexibleholding pressure of the finger structure.

Accordingly it is an object of this improvement in the art to provide aflexible artificial finger basically consisting of flesh coloredresilient plastic which is independently attachable to an artificialhand for controlled independent and cooperative movement.

Another object of this improvement in the art is to provide plasticfingers which may be straightened out but are normally and naturallyheld in a natural relaxed hand appearing position and can be bent andflexed at the principal knuckle joints in a manner resembling the normalmotion and action of the natural fingers.

Another object of this improvement in the art is to provide a flexibleplastic artificial finger stock mounted upon an improved flexingreinforcing structure about which the plastic bends to give theartificial finger a more natural appearance and natural action withnormal appearing flexibility at the points of greatest bend.

A further object of the improvement in the art is to provide a flexibleplastic artificial finger in combination with a flexible reinforcedbending knuckle and internal reinforcing flexing structure.

An additional object of this improvement in the art is to provide aflexible plastic finger stock detachably mounted on an artificial hand,the hand mechanism providing a. control forvarying the holding pressureof the finger or fingers.

Further objects and advantages will be apparent from the followingdescription of the accompanying drawings, wherein:

Finger 1 is a cross sectional top view through the finger and a portionof the knuckle section of the hand to show its attachment thereto;

Figure 2 is a cross sectional side view of Figure 1 with the finger in apartially bent position;

Figure 3 is a partial cross sectional view showing an 2. r attachment ofthe fingers to the knuckle section of the hand;

Figure 4 is a modification of Figure 3;

Figure 5 is another modification of Figure 3;

Figure 6 a sectional view of a locking ring for attaching the fingerstructure to the partial knuckle section of the hand shown in Figure 5;

Figure 7 is a plan view of the finger locking ring taken on line 7-7 ofFigure 2;

Figure 8 is a sectional view line 8-8 of Figure 2;

Figure 9 is a partial sectional view through the portion of the fingercontrol and operating mechanism in the main body or knuckle section ofthe hand.

Figure 10 is a sectional view on line 1010 of Figure 9, and

of the finger section on Figure 11 is a modification ofthe structureshown in V Figure 10.

In the following description like parts will be similarly indicated. Thepartial knuckle section of the hand is indicated by the numeral 10. Theplastic finger 11 is,

for example, amolded rubbery plastic produced in a all of which havecharacteristics of plasticity and moldability with retention ofresiliency and having a resistance to deterioration as required underconditions of use of an artificial hand. 7

As illustrated more clearly by Figures 1 and 2 taken in conjunction withFigure 8, the plastic molded finger is of a particular design havingthickened side body portions 13 and thinner top and bottom portions 14with a hollow substantially oval center aperture 15 open at the butt end16 of the finger and closed at the fingernail end 17 with a normalnatural appearing finger nail 18. The solid end 17 is provided with anarrow slot or opening 19 for mounting therein a finger movingstructure, as hereinafter described.

The outside surface of this plastic finger 11 is of a flesh colored castand molded with the usual normal appearing creases or wrinkles and foldlines 20, 21 and 22 of the hand. Also the principal finger joint contour23 appears normal and is provided with natural surface wrinkles whichgive the effect of stretching when the finger is bent.

There is molded internally of the butt end 16 a circumferential groove24 within which is mounted a holding ring 25. This ring 25 may beinserted into the groove 24] after the finger 11 is molded or mayotherwise be molded therein simultaneously with molding of the finger.The inner surface of ring 25 which extends from the edge of groove 24 isprovided, for example, with a pair of diametrically opposed'lockingslots the pin 28 into slots 27, thereby locking the ring 25 under theheads 29.

Various modifications of this finger securing and locking arrangementmay be provided. As illustrated in Figure 4, the ring 30 secured tofinger 11 in the manner as indicated for ring 25, is provided withthreaded apertures 31 within which the screw bolts 32 are turned to drawthe fingers 11 tight against the body of the hand section 10. The handsection is provided with apertures 33 which will fit the size of thebody of screw" bolts 32 and an enlarged aperture portion 34 for-entryand turning of .theheads 3.5.

' The preferied manner of attaching the plastic fingenis illustrated inFigure}. wherein solid areprpvidpd on lugs 39 and the pl astic fingereridprovidedwithihternal groove 24, fill'ed'wiith a suitable plastic tom etal cement, anld 'into which the rings 38:,areseiated Thisfprovides adust tight seal to the finger mechanism, andallso,

provides, in conjunctionwit'h' the: modifications, a means whereby wornor damaged fingerscan be replacedpas 38,"the pins 38 ar e passed and thering 36 turned to straighten the finger 11 onto the hand portion 10 andlock pins'38 behind the ring 36.

The knuckle section 19. of the hand,- as heretofore indicated, a'b odytiQ'rtioficoirtziinirig themechanism, for

example, asdes'c'rib'edin my co-pe'nding applicatiomSerial No. 460,738for Artificial Hand, of which this application is acontinuation-in-part. As more specifically shown therein, this handbodyportion ltlcontains a series of openings 49 provided with a pair ofgrooves or slots 41 designed to accommodate 'or mount finger anchoringplates 42 which form the base or support for pivoting each fingeroperating mechanism. As shown in Figure 2 the plates are mounted inthe'slots 41 and held in place by one or morepins43, in each of theplates 42, extending transversely through the hand body to hold theplates 42. and the balance of the finger plates which are likewisemounted on the section 10 of the hand. 4 7

Each of. the finger operating mechanisms are formed with raised edges 48and 49abutting against ends 50 and 51, respectively, toavoid anybackwardbend of linkages 44 and 46. l

The intermediate linkage 44,.as more clearly illustrated in Figure 8, isa U-bend piece having the ends of the opposite sides 52 and S3 turnedoutand upwardly in reverse U-bends 54 and 55 respectively. The undersurfaces of the reverse U-bends 54 and 55 are provided with a felt orother paddings S6 and 57, respectively. These paddings 56 and 57 providefora cushion'effect against which the finger body 11 is compressed in ahand or finger grasping and holding movement. A further cushioning body53 is cemented under the pivotal juncture oflinkages 44 and 46 at thefold line 22 of finger body 11. This cusha ioning body 58 may be moldedas an integral portion of finger body 11 but is preferably, arelativelyless resilient plastic or less flexible vulcanized rubberpiece which will,

withstand and resist the brunt of finger lifting pressure at the foldline 22 of the artificial finger This insert 58 can extend the fullinner length of the finger, so that a cushioning effect against thelength of the finger sections 44 and 46 isprovided or otherwise thisentire lower portion of the finger may be molded to a thickness.extending under the sections 44 and 46 as appears from consideringFigure 8 as an end view through the length of thefinger ding 57-, asshown by considering Figure 8 as anend view,

can be considered as one or more integral cushions cerncnted, by aplastic to metal bond to the finger linkage portions 44 and 46 partiallyor throughout the length thereof.

In order to more securely fasten the artificial flexible finger onto thefinger operating mechanism the linkage 46 is provided with a flattenedrounded end 59 which is held by a rubber or other cement 60' in the slotor socket 19 in the finger end 17.

The operating mechanism which controls finger movement is more fullydescribed in my above mentioned application. However, as illustrated byFigure 1 taken in conjunction with Figure 9, the connecting rodsfifi forthe one finger and 61, 62 and 63 for the balance of the fingers areconnected or hooked into the end'linkages 44 in, for example, anaperture 66 and the opposite hook end 67 is secured in an aperture 68 inplate or lever 69. The additional finger operating rods 61, 62 and 63are likewise secured in similar relationship between the other fingerend linkages and the lever 69, as described intheabove mentioned.application. The thumb action and connecting linkage therefore isnotdescribed herein. The lever 69 is pivotally connected to a suitableboss. 70 forming aportion of the hand section 10. A screw, pin or rivet71pivotally secures lever 69 to the boss 79. Pivotally connected totheopposite end of lever 69 is a pull lever 72. The lever 69. and lever 72are pivotally mounted on a suitable rivet, pin or bolt 73. In this casethe levers 69 and 7?. are pivoted on a threaded bolt 73 provided with alocking nut 74. Intermediate the ends of lever 72 there is provided anaperture75 through which a hooked end 76 of linkage 77 is fastened withthe opposite hooked end 78 fastened through a suitable aperture in theend of the second finger fastening plate 42. A spring 80 extends betweenthe side of the hand body Iii-fastened thereto by pin 81 and to the link77 by hook end 82' so as to hold the link 77 in position with fingersnormally relaxed. The linkend 75 serves as a pivot point so that lever72 actuates the lever 69 to open the fingers when pull cord 81 is undertension. Pull cord 81 is .of a conventional pivotally connected typeattached to pull lever 72 by pivot pin or rivet connection 82.

In order to obtain an adjustable variation of holding pressure by thefingers there is provided a first spring 83 secured at one end to buttplate 90 0f hand section 10 and at the opposite end by integral hook end84 extending through a suitable aperture in the lug or ear 85 at the endof the lever 69 connected to the thumb control rod,

for example 73, and finger rods 60,61, 62 and 63. A second spring 86overrides the spring 83 having its one integral hook end 87 secured in asuitable aperture in car 85 and its opposite end 85 unfastened andordinarily freely slidable over spring 83. The end 88 of spring 86, i.e. the end ring, is provided with a pair of ears or similar projections89 at opposite diametrical sides. These cars 89 may be provided, forexample, by bending or stretch: ing the spring end 88 on diametricallyopposite sides as at 89.- On the butt plate 90 of the wrist section ofthe 91 fastened to plate 90 by screw 92 secured through the hand portion10 there is provided a slidable locking key slot 93 of key 91. The innerend of key 1 is provided with the spaced ears or dogs 94 which slidablyfit over spring 86, and engage or lock the ears 89v andthe end 83 ofspring 86 substantially to the plate 90. The plate 90, as illustrated inFigures 9 and 10, extends outwardly through a slot in the side of thewrist sectiond and is provided with a finger flange 95. by which thelocking key 91 is moved to lock and free the end 88. of spring 86, asdescribed.

As illustrated in Figure 11, the locking key 91 is fastened to plate 90by a pair of screws 92 extending through slot 93 and the operatingflange 96 extends through a suitable slot in the underside of the wristportion of hand section 10. The locking key 91, in this instance, isthereby moved from underneath the wrist section rather than from theside. A suitable aperture 97 is provided in the butt plate 90 for thepull cord 81. This aperture may be m alignment with the slot 93 desired.Accordingly, the closing and holding forces of the fingers are dependentupon whether the tension of spring 86 is applied simultaneously with thetension of spring 83. As provided for by the resilience of the plasticfingers, when required or desirable, a very strong holding pressure maybe used to grasp relatively fragile articles without breakage. In makingup the artificial hand the thumb and one or more of the fingers may beof the flexible plastic character as herein disclosed and the balanceeither structures of the prior art or of the character of a springstructure provided with a partial plastic, e. g. vinyl, coating as shownin my above mentioned application. Further the plastic fingers may beconstructed, as illustrated for example Without pigmentation or fleshcoloring, and then covered with the thin flexible material.

In accordance with the patent statutes, I have described the principlesof construction and operation of my improvement in artificial fingersand hand mechanism, and while I have endeavored to set forth the bestembodiment thereof, I desire to have it understood that obvious changesmay be made within the scope of the following claims without departingfrom the spirit of my invention.

I claim:

1. A replaceable flexible plastic artificial finger capable of graspingfragile objects under different and variable pressures including incombination a hollow plastic body provided with flexible side wallsections and relatively flexible top and bottom wall sections, an openend section, a solid closed end section, and said open end sec tionprovided with looking ring and collar securing means for mounting saidplastic finger in abutting relationship to the knuckle section of anartificial hand.

2. The structure of claim 1 wherein the separable plastic hollow bodycontains operating mechanism fastened to the said closed end section,and an operating lever extending from said open end section.

3. The structure of claim 2 wherein said operating lever is providedwith control means for varying the moving force of said finger operatingmechanism.

4. The structure of claim 3 wherein said control means comprises avariable spring force of adjustable resistance.

5. An artificial hand including in combination a plurality of separableresilient fingers anchored to the knuckle section of the hand andvariable finger pressure operating mechanism, said resilient fingerscomprising hollow rounded plastic bodies having relatively flexible sidewall sections and flexible top and bottom sections, an open end securedin separable abutting relationship to said knuckle section and arelatively solid closed end section, pivotal finger operating linkagesconnected to said closed end section, lever means connected to saidoperating linkages, and adjustable spring means connected to said levermeans for controlling the operating tension applied to said linkages,said adjustable spring means comprises one spring member permanentlyattached between said lever means and the knuckle section of said handand a second adjustable tensioning means mounted on said knuckle sectionfor varying the operating tension on said linkages.

6. The structure of claim 5 wherein the second adjustable tensioningmeans is a second spring adapted to be attached to and detached from thesaid knuckle section to increase the relative operating tension of saidlinkages and release the increase of relative operating tension respectively.

7. in combination in an artificial hand provided with a flexible fingersection, a knuckle section and a wrist section operating mechanism torchanging the relative oper ating tension of said flexible finger sectioncomprising linkage means in said finger section, an operating leverconnected to said linkage means, a pull lever connected to saidoperating lever, primary tensioning means connected between saidoperating lever and said knuckle section, and secondary tensioning meansfor increasing the relative operating tension of said flexible fingersection.

8. In the structure of claim 7 a locking means for controlling saidsecondary tensioning means.

9. in the structure of claim 7 said primary tensioning means comprisinga spring means permanently attached between said operating lever andsaid knuckle section and said secondary tension means comprising anauxiliary spring means having at least one end free of any attachmentduring the absence of any increase in operating tension and both endssecured when the operating tension is increased.

10. An artificial hand structure provided with flexible fingersincluding in combination operating mechanism for flexing said fingers,said operating mechanism comprising finger linkage means secured at oneend in the finger structure and at the opposite end to finger flexinglevers under spring tension, spring means for controlling the flexingtension of said finger operating mechanism, auxiliary spring means forincreasing the operating tension of said finger linkage means, andlocking means for detachably securing the auxiliary spring means duringan increase of operating tension.

11. An independently replaceable finger structure for an artificial handcapable of grasping objects at different pressures in combination with ahand body comprising a flexible and resilient hollow body havingflexible tubular walls and a solid closed end provided with afingernail, and cooperable detachable connecting means on the other endof said hollow body and said hand including a ring and groove means.

12. An independently replaceable finger structure for an artificial handin combination with a hand body comprising a flexible and resilienthollow body having flexible tubular walls and a solid closed end,cooperable detachable connecting means on the other end of said body andon said hand for detachably connecting the same, the closed end of saidhollow body having an internal socket therein, finger actuatingmechanism on said hand body extending into said hollow body, and meansreleasably anchoring the end of said finger actuating mechanism in saidsocket.

13. An independently replaceable finger structure for an artificial handin combination with a hand body comprising a flexible and resilienthollow body having flexible tubular walls and a solid closed end,cooperable detachable connecting means on the other end of said body andon said hand for detachably connecting the same, finger actuatingmechanism including an anchoring member secured to said hand body, linkmeans pivotally connected to said anchoring member extending into saidhollow body, and link actuating means connected to said link means, andmeans releasably connecting the end of said link means to said hollowbody adjacent to the closed end thereof.

References Cited in the file of this patent UNITED STATES PATENTS

